How to get point value in app designer plots?

Hello everyone.

Is there a way to get a point value from a plot using the mouse cursor in appdesigner? This is my code in a script file and it works pretty good but I can't translate it into the AppDesigner world.

% Other code lines
if app.qq==1
    i=1;
    dcm_obj = datacursormode;
    set(dcm_obj,'DisplayStyle','window','SnapToDataVertex','on','Enable','on')
    waitforbuttonpress
    c_info{i} = getCursorInfo(dcm_obj); %#ok
    Freq_line=c_info{1,i}.Position(1);
    idx=find(app.H.f==Freq_line);
    app.qq=2;
    q=1; %#ok
end
% Other code lines

I gave a look online but it seems that both datacursormode and waitforbuttonpress don't works in AppDesigner. I didn't find any answer yet and I hope someone could help me.

Thank you in advance for your reply.

Answer 1

[Adam Danz]

Provide the app's figure handle in your call to datacursormode.

The window DisplayStyle is not supported in UIfigures.

The default value to SnapToDataVertex is on so you don't need to include that.

dcm_obj = datacursormode(app.MyAppUIFigure);
dcm_obj.Enable = 'on';

I'm not sure what cursorInfo is in your code.

update

In 2019b, after executing the lines above if the mouse hovers over a data point and creates a data tip, the following warning appears. Apparently this functionality hasn't been rolled out yet.

Warning: Error occurred while executing the listener callback for event WindowMouseMotion defined for class matlab.ui.Figure:

Error using matlab.ui.Figure/set

Functionality not supported with figures created with the uifigure function. For more information, see Graphics Support in App Designer.

Error in setptr (line 386)

An alternative would be to use the data tips by hovering the mouse over a data point. This code below waits for a data tip to appear and then extracts its coordinates.

tth = findall(app.UIAxes,'Type','hggroup');     % find any pre-existing data tips
delete(tth)                                     % remove them
tth = [];
while isempty(tth)
     tth = findall(app.UIAxes,'Type','hggroup');
     pause(0.1) % important, without it Matlab crashes
end
disp(tth.Position)

[Davide Mastrodicasa]

Thank you Adam for your suggestion. It worked and I don't really need the window DisplayStyle.

The only problem I have now is that the waitforbuttonpress works only with figure and therefore it opens a new re where I have to click on order to go ahead with my app. Is there a similiar function that do the same in AppDesigner?

[Adam Danz]

At the top of the page you shared, it states, "Use this function only with GUIDE, or with apps created with the figure function." That warning indicates that the function isn't suppored by appdesigner. waitfor() may be useful. You can set it up so it waits for a property of an object to change and that property could be related to the datacursor. I haven't played around with it but that's an idea to try out.

waitfor(obj,propname)

Update: see my updated answer for a problem with datacursormode in uiaxes.

[Davide Mastrodicasa]

Ok perfect. I solved also the other problem of the waitforbuttonpress using waitfor(obj,propname) and adding another button.

Thank you very much for your help Adam